Note: Descriptions are shown in the official language in which they were submitted.
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SAFETY PIPE WRENCH
TECHNICAL FIELD
[0001] The invention relates generally to sliding-jaw pipe wrenches.
BACKGROUND
[0002] Lightweight, sliding-jaw, pipe wrenches are described in, for example,
U.S.
Patent Nos. 2,656,751 (issued to W. J. Johnson et al.) and 2,680,984 (issued
to C.
H. Ingwer). FIG. 1 shows a lightweight, sliding-jaw pipe wrench from U.S.
Patent
No. 2,656,751 (the `751 patent). The pipe wrench of FIG. 1 consists of a
handle 10
having a fixed jaw 11 and an integral frame 12 through which extends a
threaded
shank 13 of a movable jaw 14, which is adjustable relative to the jaw 11 by a
nut 15
engaging the shank 13 and supported and retained between the frame 12 and a
pair
of bosses 16. The jaws 11 and 14 are provided with replaceable jaw inserts 17
and
18, respectively. The `751 patent describes the pipe wrench as being formed
essentially of a metal or alloy that is lightweight and that does not have as
high a
yield point under proof as malleable iron and steel. The `751 patent describes
designing and proportioning various elements of the pipe wrench to compensate
for
the low yield point of the lightweight material. For example, as disclosed in
the `751
patent, the handle 10 has an H transverse cross-section.
[0003] Pipe wrenches such as described above are available in the market. For
example, the Rigid Tool Company makes a variety of such pipe wrenches under
the
trade name RIDGID . Lightweight, sliding-jaw, pipe wrenches such as described
above are commonly used in downhole tool service facilities to apply high
connection makeup torques. Typically, these wrenches are attached to an
overhead
crane when being used. Safety has been a concern with these wrenches when
operating at high torque loads. Bent handles and fractured jaws are a common
occurrence for such wrenches, which can result in jaws becoming air borne,
handles
swinging free violently, and overhead cranes being shocked and potentially
damaged.
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SUMMARY
[0004] One aspect of the present invention relates to a safety pipe wrench.
The
safety pipe wrench comprises a Y-shaped handle having a stem extending from a
first end of the handle towards a second end of the handle. The stem
bifurcates into
a first arm and a second arm at a location between the first end and the
second end
of the handle. The first arm and the second arm extend to the second end of
the
handle. A slot is defined between the first arm and the second arm. The safety
pipe
wrench comprises a first gripping insert mounted on the first arm. The safety
pipe
wrench comprises a nut rotatably retained in the slot. The safety pipe wrench
comprises a jaw having a shank terminating in a jaw head. The shank is movably
engaged with the nut. The safety pipe wrench comprises a second gripping
insert
mounted on the jaw head.
[0005] Additional aspects of the present invention will be apparent from the
following detailed description and the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0006] The following is a description of the figures in the accompanying
drawings.
The figures are not necessarily to scale, and certain features and certain
views of
the figures may be shown exaggerated in scale or in schematic in the interest
of
clarity and conciseness.
[0007] FIG. 1 is a side view of a prior-art pipe wrench.
[0008] FIG. 2 is a side view of a safety pipe wrench according to an
embodiment
of the present invention.
[0009] FIG. 3 is a perspective view of the safety pipe wrench of FIG. 2.
[0010] FIG. 4 is a close-up view of a portion of the safety pipe wrench of
FIG. 2.
[0011] FIG. 5 is a perspective view of a gripping insert.
DETAILED DESCRIPTION
[0012] In the following detailed description, numerous specific details may be
set
forth in order to provide a thorough understanding of embodiments of the
invention.
However, it will be clear to one skilled in the art when embodiments of the
invention
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may be practiced without some or all of these specific details. In other
instances,
well-known features or processes may not be described in detail so as not to
unnecessarily obscure the invention. In addition, similar or identical
reference
numerals may be used to identify similar or common elements.
[0013] FIG. 2 is a side view of a safety pipe wrench 31 according to an
embodiment of the present invention. FIG. 3 is a perspective view of the same
pipe
wrench. Referring to FIG. 2 or 3, the pipe wrench 31 has a flat, Y-shaped
handle 33
with a bottom end 35 and a top end 37. The terms "top" and "bottom" are
relative to
the orientation of the drawing shown in FIG. 2. The Y-shaped handle 33 has a
stem
39, which extends from the bottom end 35 towards the top end 37. The stem 39
bifurcates at a location 41 between the bottom end 35 and top end 37 into a
left arm
43 and a right arm 45. The terms "left" and "right" are relative to the
orientation of the
drawing shown in FIG. 2. The left arm 43 and right arm 45 extend along
parallel
paths to the top end 37 of the handle 33. The stem 39, left arm 43, and right
arm 45
form a Y-shape, hence the term "Y-shaped handle." The left arm 43 and right
arm 45
provide parallel load paths, as opposed to the cantilever load path of a
traditional
handle such as shown at 10 in FIG. 1. The Y-shaped handle 33 is made of a
ductile
and malleable metal or alloy. A suitable material is high-strength aluminum
alloy
such as used in the aircraft industry. The aluminum alloy may be anodized.
[0014] Multiple slots 49 are formed in the stem 39. The slots 49 are spaced
apart
along a longitudinal axis 51 of the handle 33. The longitudinal axis 51 is a
median
line running from the bottom end 35 of the handle 33 the top end 37 of the
handle
33. The slots 49 may have the same or different cross-sectional areas. In the
drawing of FIG. 2, the cross-sectional areas of the slots 49 are increasing
along the
longitudinal axis 51, from the bottom end 35 towards the location 41 at which
the
stem 39 bifurcates into the left arm 43 and right arm 45. The slots 49 in the
stem 39
serve at least two purposes. The first purpose is to reduce the weight of the
stem 49
or the amount of material used in making the stem 49. The second purpose is to
disrupt crack propagation across the width of the stem 39 (width is measured
transverse to the longitudinal axis 51). For illustration purposes, if a crack
starts in
the stem 39, the crack will most likely start at a thinner section of the stem
adjacent
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to one of the slots 49. Such a crack will not be able to propagate across the
width of
the stem 49 because the slot 49 near the crack would disrupt propagation the
crack.
The slots 49 and the ductile material used in making the handle 33 help avoid
the
case of flying handles when the safety pipe wrench 31 is used to make up high
torque connections.
[0015] The left arm 43 and right arm 45 are spaced apart so that a slot 53 is
defined between them. The slot 53 is open at the top end 37 of the handle 33.
The
width of the left arm 43 is different from that of the right arm 45 so that
the slot 53 is
eccentric relative to the longitudinal axis 51 of the handle 33 (width is
measured
transverse to the longitudinal axis 51). The slot 53 is also eccentric
relative to the
slots 49 in the stem 39. However, in alternate embodiments, the slot 53 may
not be
eccentric relative to the longitudinal axis 51 and slots 49, and the width of
the left
arm 43 and right arm 45 may be roughly equal.
[0016] A shackle 55 is attached to the bottom end 35 of the handle 33. The
shackle 55 can be used to couple the handle 33 to a machine such as an
overhead
crane. The shackle 55 is attached to the bottom end 35 of the handle by
inserting an
adjustable lock 56 into aligned holes (not visible in the drawing) in the
shackle 55
and bottom end 35 of the handle 33. The hole in the handle 33 (through which
the
adjustable lock 56 is inserted) may be profiled to achieve low stress. The
shackle 55
is made of a ductile and malleable material. A suitable example is high-
strength alloy
steel such as 4340 alloy steel.
[0017] A jaw 57 has a shank 59 terminating in a jaw head 61. The jaw 57 is
made
of a ductile and malleable material. A suitable example is high-strength alloy
steel
such as 4340 alloy steel. Teeth or threads 63 are formed on opposite sides of
the
shank 59. The shank 59 is inserted into a bore of a nut 65. (The nut 65
includes
cylindrical body with a bore.) The bore of the nut 65 is threaded so that the
nut 65
can engage the shank 59 and also rotate relative to the shank 59. The nut 65,
with
the shank 59 extending through its bore, is disposed in the slot 53. The bore
of the
nut 65 is in an upright orientation (relative to the orientation of the
drawing in FIG. 2)
so that it is accessible from the top end 37 of the handle 33 or so that the
shank 59
extends out of the slot 53 through the top end 37 of the handle 33. As the nut
65 is
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rotated, the shank 59 moves relative to the nut 65, where the rotational
direction of
the nut 65 determines whether the shank 59 is extended or retracted relative
to the
slot 53.
[0018] Referring to Figures 2-4, the nut 65 and the shank 59 are retained in
the
slot 53 by two side plates (or surfaces) 67, 69. The side plate 67 is attached
to the
left arm 43 and the right arm 45 and from the front side 71 of the handle 33.
The side
plate 69 is attached to the left arm 43 and the right arm 45 from the backside
of the
handle 33 (the backside is in opposing relation to the front side 71). Again,
the terms
"front side" and "backside" are relative to the orientation of the drawing in
FIG. 2.
The side plates 67, 69 have windows 73 (the window for the side plate 69 is
not
visible in the drawing but is in opposing relation to the window of the side
plate 67)
through which the nut 65 in the slot 53 can be accessed. The nut 65 juts into
the
windows 73 and is encompassed and constrained by the windows 73. To explain
further, the thickness of the side plate 67 at a top wall 77 of the window 73
serves as
a top stop for the nut 65. The thickness of the side plate 67 at the bottom
wall 79 of
the window 73 serves as a bottom stop for the nut 65. The width of the window
73,
i.e., the distance between the side plates 67, 69 about the window 73, is
smaller
than the diameter of the nut 65 so that the nut 65 cannot fall through the
window 73.
The preceding explanation about how the window 73 in the side plate 67
encompasses and constrains the nut 65 is also applicable to the side plate 69.
The
portions of the side plates 67, 69 below the windows 73 also constrain the
shank 59
in the slot 53.
[0019] Each of the side plates 67, 69 is attached to both the left arm 43 and
the
right arm 45. In FIG. 4, the side plate 67 is attached to the left arm 43 and
the right
arm 45 at a total of three points, where the three points are not all on a
line or are
not all collinear. Additional attachment points between the side plate 67 and
the
arms 43, 45 may be provided. In FIG. 4, the bolts 85 represent the attachment
points
between the side plate 67 and the arms 43, 45. The bolts 85 include threads
for
engaging the arms 43, 45, but other fasteners besides bolts could be used for
the
attachment points. One bolt 85 is used between the side plate 67 and the right
arm
45, and two bolts 85 are used between the side plate 67 and the left arm 43.
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single attachment point between the right arm 45 and the side plate 67 serves
as a
slight hinge to transfer load to the left arm 43. The explanation above about
attachment of the side plate 67 to the arms 43, 45 is equally applicable to
the
attachment of the side plate 69 to the arms 43, 45. The side plates 67, 69 are
made
of a ductile and malleable metal or alloy. A suitable example is high-strength
alloy
steel such as A514 alloy steel. The side plates 67, 69 may be provided as
separate
parts. Alternatively, the side plates 67, 69 may be provided as a single part.
The
single part would include surfaces that correspond to the side plates and a
bridge
surface connecting the surfaces. The bridge surface could sit on the top end
37 of
the handle 33 with the surfaces that correspond to the side plates depending
downwardly from the bridge.
[0020] A gripping insert 89 is mounted on the right arm 45. Any of a variety
of
gripping inserts may be mounted on the right arm 45. FIG. 5 is a perspective
of the
particular gripping insert 89 shown in FIGS. 2-4. The gripping insert 89
includes
teeth 91 formed on a front face 92 of an insert body 93. The teeth 91 are for
gripping
an object, such as a pipe. A ridge 95 is formed on the backside 96 of the
insert body
93. A hole 97 is formed in the ridge 95. A corresponding slot is formed at the
top end
of the right arm to receive the ridge 95 (the right arm is shown at 45 in FIG.
4, and
the top end of the right arm is the surface of the right arm on which the
gripping
insert 89 is mounted). When the gripping insert 89 is mounted on the right arm
(45 in
FIG. 4), the hole 97 in the ridge 95 is aligned with holes in the right arm,
and a bolt
(99 in FIG. 4) is inserted into these aligned holes and secured in place via a
nut (the
holes in the right arm are not visible, but one of the holes would be where
the bolt 99
is shown in FIG. 4). A key 101 is also formed on the backside 96 of the
gripping
insert 89. The key 101 is an elongated bar. The key 101 fits into another slot
at the
top end of the right arm (45 in FIG. 4) when the gripping insert 89 is mounted
on the
right arm. In the embodiment shown in FIG. 5, the key 101 is integrally formed
with
the insert body 93. However, it is possible to also provide the key 101 as a
separate
component that will be inserted in between the insert body 93 and the top end
of the
right arm (45 in FIG. 4). The key 101 helps distribute load applied between
the
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gripping insert 89 and the top end of the right arm (45 in FIG. 4). The
gripping insert
89 may be made of a ductile and malleable material, such as hardened alloy
steel.
[0021] Returning to FIG. 4, the jaw head 61 is located above the top end 37 of
the handle 33. A gripping insert 103 is mounted on the jaw head 61. When the
pipe
wrench 31 is assembled for use, the position of the jaw head 61 is such that
the
gripping insert 103 on the jaw head 61 is opposite to the gripping insert 89
on the
right arm 45. The opposed gripping inserts 89, 103 can cooperatively grip an
object
of interest. The nut 65 can be rotated to extend or retract the shank 59 from
or into
the slot 53, respectively, in order to adjust the distance between the opposed
gripping inserts 89, 103 - the distance between the gripping inserts 89, 103
increases as the shank 59 is extended and decreases as the shank 59 is
retracted.
As in the case of the right arm 45, any of a variety of gripping inserts may
be
mounted on the jaw head 61. For illustration purposes, the gripping insert 103
may
be the same as the gripping insert 89 shown in FIG. 5 and explained above. To
accommodate the gripping insert 103, suitable slots are formed in the jaw head
61 to
receive the ridge (hidden behind the gripping insert 103) and key 105. The key
105
may or may not be integrally formed with the gripping insert 103 but is
embedded in
the end face of the jaw head (i.e., the face of the jaw head in contact with
the
backside of the gripping insert 103) and serves the same purpose as described
above for the key 101.
[0022] Other types of gripping inserts and method of mounting the gripping
inserts are known in the art and can be used in place of the gripping insert
described
in FIG. 5. See, for example, U.S. Patent No. 2,656,751 (issued to W. J.
Johnson et
al.), which discloses jaw inserts with dovetail mortises and corresponding
dovetail
tenons formed in jaws to engage with the dovetail mortises.
[0023] Referring to FIG. 2, a slot 48 formed in the right arm 45 provides a
pick-up
point for the handle 33. The pick-up point allows an operator to easily pick
up the
wrench 31 one-handed while the wrench 31 is attached to an overhead crane or
other overhead device. The pick-up point provided by the slot 48 is properly
balanced so that the shackle 55 tends to fall lower than the jaw head 61 in
order to
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allow the jaw head 61 to grip an object while the operator holds onto the
wrench 31
with one hand and controls the crane with the other hand.
[0024] While the invention has been described with respect to a limited number
of
embodiments, those skilled in the art, having benefit of this disclosure, will
appreciate that other embodiments can be devised which do not depart from the
scope of the invention as disclosed herein. Accordingly, the scope of the
invention
should be limited only by the attached claims.
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